Stilobezzia (Eukraiohelea) proxima Cazorla & Felippe-Bauer, 2017

Bauer, Maria Luiza Felippe, 2017, Contributions to the knowledge of predaceous midges of the subgenus Eukraiohelea Ingram & Macfie of Stilobezzia Kieffer (Diptera: Ceratopogonidae), from Brazil, Zootaxa 4324 (3), pp. 557-570 : 562-563

Stilobezzia (Eukraiohelea) proxima Cazorla & Felippe-Bauer n. sp.

( Figs. 15 ¯28)

Diagnosis. The only Neotropical species of Stilobezzia (Eukraiohelea) of large size (wing length 1.50 – 1.82 mm) with pale yellowish coloration and the lateral margins of abdominal tergites with dark brown stripes. Male with stout gonocoxites; gonostyli short, swollen at mid portion with curved apex and pointed tip; apicolateral processes short, rounded and parameres with short, ventrally directed tip. Female with tarsomere 5 of fore and mid legs with 2 pairs of batonnets, tarsomere 5 of hind leg with 1 pair of batonnets and two ovoid spermathecae measuring 87–90 µ.

Male ( Fig. 15 ). Head ( Fig. 16 ) dark brown. Antenna with flagellomeres 1–10 pale yellowish basally, light brown distally, flagellomeres 11–13 dark brown with light brown basal ring; flagellomere 13 2.5X longer than flagellomere 12; plume brown, poorly developed; antennal ratio 1.30. Palpus ( Fig. 17 ) with segments 3–5 dark brown, 1–2 light brown; third segment elongate with subapical sensory pit; palpal ratio 3.50 (n = 2).

Thorax. Scutum brown (as Fig. 15 , female), two faint yellowish lateral vittae extending posteriorly from paler humeral pits; scutellum pale yellowish except narrow lateral margins brown with 4 stout setae, 2–3 thinner setae; postscutellum brown. Legs pale yellowish; basal 1/3 of mid tibia slightly darker; narrow apex of hind femur dark brown; basal 1/3, narrow apex of hind tibia dark brown; fore femur with 2–3 short stout ventral spines; tarsomere 1 of mid leg with slender, straight basal spine; tarsomere 1 of hind leg with stout, curved basal spine; hind tibial comb with 6 spines; fore leg tarsal ratio 2.41–2.45 (2.43, n = 2); mid leg tarsal ratio 2.78–2.90 (2.79, n = 2); hind leg tarsal ratio 2.69–2.88 (2.79, n = 2); tarsomere 5 of all legs with 1 pair of batonnets ( Fig. 18 ) and large claws with long basal tooth. Wing ( Fig. 19 ) membrane hyaline; r-m crossvein oblique; cubital fork distal to level of base of rm crossvein; wing length 1.50–1.63 (1.57, n = 2) mm, width 0.50 (n = 2) mm; costal ratio 0.72–0.75 (0.73, n= 2). Halter stem dark brown; basal half of knob dark brown, distal half pale.

Abdomen. Pale yellowish, lateral margins of tergites brown. Genitalia ( Figs. 20 ¯22): tergite 9 extending slightly beyond apex of gonocoxites, distal margin rounded with small mesal notch, apicolateral processes short with rounded apices, located laterad to the slender cerci ( Fig. 22 ); sternite 9 2.50 X broader than long, posterior margin not clearly distinguishable, apparently straight. Gonocoxite stout, 2.0 X longer than greatest breadth, each with a hyaline membrane extending from the dorsal inner margin to nearly 2/3 of the length of parameres, lateral broad margins of the membrane sclerotized, folded, connected dorsally by a broad, sclerotized transversal bridge; gonostylus pale yellowish, 0.60 X the length of gonocoxite, swollen at mid portion, tip curved, pointed. Parameres separate, parallel; gonocoxal apodemes moderately sclerotized, broad, fused to dorsum of basal arms of parameres; basal arms stout, blade-like, apices rounded, divergent; distal portions slender, rod-like, closely approximated except on apices, which gradually taper to slightly broader ventrally recurved, pointed tips. Aedeagus represented by 2 arched sclerites; basal portion heavily sclerotized, recurved; subapical portion slightly swollen, more lightly sclerotized; distal portion pointed, tips overlapping.

Female. Similar to male, with the following notable sexual differences: Head ( Fig. 23 ). Antenna with flagellomeres 1–8 pale yellowish basally, pale brown distally, flagellomeres 9–13 dark brown with pale basal ring; antennal ratio 1.73–1.92 (1.82, n = 2). Palpal ratio 3.50–3.75 (3.60, n = 2). Mandible with 7 – 8 teeth.

Thorax. Legs ( Fig. 24 ): fore femur with 2 – 4 short, stout ventral spines; tarsomere 5 of fore and mid legs with 2 pairs of batonnets, tarsomere 5 of hind leg with 1 pair of batonnets ( Fig. 25 ); fore leg tarsal ratio 2.33– 2.44 (2.38, n = 2); mid leg tarsal ratio 2.65–2.72 (2.68, n = 2); hind leg tarsal ratio 2.75–2.86 (2.80, n = 2); claws slightly shorter than their respective tarsomeres 5, with moderately long basal tooth. Wing ( Fig. 26 ) length 1.75–1.82 (1.78, n = 2) mm, width 0.65–0.68 (0.66, n = 2) mm; costal ratio 0.76–0.77 (0.76, n = 2).

Abdomen. ( Fig. 27 ). Broad lateral margins of segment 8 dark brown. Genitalia ( Fig. 28 ): sternite 8 pale, narrow, with U-shaped posteromedian excavation; sternite 9 halves heavily sclerotized, anterior margins straight, posterior margins curved, apices broader, decumbent; sternite 10 pale with 3–4 pairs of setae; cercus rounded, short. Two subequal, ovoid spermathecae with short, moderately wide necks, measuring 90 by 57 (n=2) µ and 87 by 57 (n = 2) µ; a small, spheroid rudimentary third spermatheca measuring 12–15 (13.5, n = 2) µ.

Distribution. Brazil (Rio de Janeiro).

Types. Holotype male, labeled “Holotype Stilobezzia (Eukraiohelea) próxima Cazorla and Felippe-Bauer , BRAZIL, Rio de Janeiro, Casimiro de Abreu, Union Biological Reserve (22°25’35” S 42°2’4” W), 07.XI – 13.XII.2013, "Biota Diptera Fluminense " team col, Malaise trap, (CCER). Allotype female, 1 male paratype with same data as holotype (CCER); other paratypes, 1 male, 1 female with same data except 25.VIII–26.XI.2013 ”, (CCER).

Etymology. The species name proxima (from Latin = near), refers to the resemblance of this new species with Stilobezzia (E.) elegantula and S (E.) quasielegantula n. sp. described below.

Discussion. Stilobezzia (E.) proxima n. sp. greatly resembles S. (E.) elegantula and S. (E.) quasielegantula n. sp. by its overall pale yellowish coloration, but it readily differs from two dark brown species, S. amnigena and S. dorsofasciata . Females of S. proxima are distinguished from the above two pale species in the subgenus Eukraiohelea by several characters: the larger wing (female wing length 1.33–1.48 mm in elegantula and 1.30– 1.37 mm in S. quasielegantula ); larger spermathecae (spermathecae 50–58 mm long in S. elegantula and 48–65 mm long in quasielegantula ); the absence of dark marks on the abdominal tergites (dark brown L-shaped marks in S. elegantula , dark brown transverse bands with pale spots in S. quasielegantula ), and only one pair of batonnets on tarsomere 5 of the hind leg (two pairs of batonnets on tarsomere 5 of the hind leg in elegantula ). The males of this new species and those of S. quasielegantula have well developed apicolateral processes, which are apparently absent in S. elegantula ; the gonostylus is swollen at midportion, whereas it is subapically swollen in S. quasielegantula , and in S. elegantula is slender; finally, the apicolateral process are short and rounded (they are moderately elongate and lobe¯shaped in S. quasielegantula , but are absent in S. elegantula ).

Figures

FIGURES 15 – 22. Stilobezzia (Eukraiohelea) proxima Cazorla & Felippe-Bauer n. sp. Male. 15. thorax and abdomen, dorsal view. 16. head, frontal view. 17. apex of proboscis and palpi. 18. tarsomeres 5 and claws. 19. wing. 20. genitalia, ventral view. 21 genitalia, dorsal view. 22 detail of cerci and apicolateral processes. Scale bars: 0, 0 5 mm.

FIGURES 23 – 28. Stilobezzia (Eukraiohelea) proxima Cazorla & Felippe-Bauer n. sp. Female. 23. head, frontal view. 24. trochanters, femora and tibiae. 25. tarsomeres 5 and claws. 26. wing. 27. abdomen, ventral view. 28. sternites 6 – 10 of abdomen and spermathecae, ventral view. Scale bars: 0, 0 5 mm.